Influence of crosslinking degree on Cu(II) and Fe(III) adsorption capacity of hy drogel/montmqrillonite composites

摘要

Intercalation of polyacrylamide (PAAm) and poli(acrylic acid) (PAA) into interlayer spaces of natural montmorillonite by the in situ polymerization technique was studied. The modifications were carried out with using both the raw and pre-treated clay. It was shown that no initial modification of the layered mineral (by ion-exchange with Na~+ cations or organophilization) is needed for the successful introduction of hydrogels into the interlayer gallery. The effect of kind of polymer and its crosslinking degree (with N,N'-methylenebisacrylamide, MBA) on the structure of the obtained composites was investigated. The polyacrylamide-containing materials exhibited a tendency to the formation of exfoliated structure. Finally, the composites were tested in a role of adsorbents in an elimination of transition metal cations (Cu~(2+) and Fe~(3+)) from aqueous solutions. The highest adsorption capacity was achieved on the poly(acrylic acid)/montmorillonite composite with the hydrogel crosslinked with MBA at the MBA/monomer molar ratio of 0.01.